DE2543663A1 - BURST PROTECTION ARRANGEMENT FOR MAJORLY CYLINDRICAL DESIGNED STEAM GENERATORS, PREFERABLY FROM PRESSURE WATER NUCLEAR POWER PLANTS - Google Patents

Description

KRAFTWERK UNION AKTIENGESELLSCHAFT Our mark:

M VPA 75 P 8 5 2 6 BRO

Burst protection arrangement for essentially cylindrical designed steam generator, preferably from Druckwasserke rnkra ftwe rke η

The invention relates to a burst protection arrangement for substantially cylindrical steam generator, preferably from pressurized water nuclear power plants, with a steam generator surrounding burst protection cover with base, cover and jacket made of tensile and pressure-resistant material, in particular steel, whereby The base, cover and jacket are connected to one another by means of axially loadable connecting means, and the jacket is made up of cylinder sections consists.

Such an arrangement is known from DT-OS 2 258 226. Its job is to provide a break in the steam generator Damage to the containment and more relevant in terms of safety Prevent facilities. In particular, in the known steam generator burst protection, the arrangement is made so that between the outer burst protection cover and the steam generator an intermediate layer enveloping the steam generator in the jacket area made of pressure-resistant, heat-insulating material, preferably in the form of insulating concrete segments, is provided. Such The insulating layer is useful for the uniform application of force and therefore also useful for the outer burst protection covering a lower temperature level than the steam generator. This arrangement works so that in the event of a round crack of the Steam generator bottom and cover are held together by axial clamping elements, which are not or only during normal operation are weakly biased. Here, the cover, which is designed as a plate-shaped body, is essentially open Train claimed, apart from its edge area where the axial tensioning elements are anchored.

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The invention is based on the consideration that the stress conditions with such a cover can be made cheaper, so that both a material saving can be achieved, and a divisibility of the cover is made possible, which is advantageous in terms of assembly. The invention is therefore based on the task of creating a burst protection cover which can be manufactured in a lighter construction and which also with regard to an easy assembly and disassembly is improved.

This object is achieved according to the invention in a burst protection arrangement of the type explained in more detail at the outset in that the Lid consists of an inwardly curved, divided spherical shell and an undivided support ring that the spherical shell as a separate component with its outer edge surface on an inner ring surface of the support ring and that the support ring by means of the axially loadable connecting means in the association of soil, Lid and jacket is included. The advantages achieved by the invention are mainly to be seen in the fact that the lid as inwardly curved spherical shell is only subjected to pressure in the event of a burst, which means a gain in safety Support ring can be designed and dimensioned in such a way that it absorbs the axial and, above all, radial forces that occur in the event of a burst, which emanate from the spherical shell, safely intercepts. By dividing the upper lid, it is possible to use the steam generator Exiting live steam line should also be carried away centrally, as with previous steam generators. The repeat test of the steam generator necessary dismantling of the lid can namely due to the split design even with centric Main steam line can be easily carried out. A preferred embodiment of the invention consists in a steam generator, in which the live steam pipeline emerges centrally from its housing cover surface is led out, accordingly in the fact that the buttocks of the cover are placed through the pipe axis and the Shell parts of the cover encompass the pipeline with sector-shaped recesses on its inner circumference. Is preferred The spherical shell is divided into two shell halves, since such a division already facilitates the assembly required brings itself, whereby the lid vault remains strong enough.

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According to a further development of the invention, the support ring consists of an inner ring part which is used to hold the vertical component the lid force and to introduce this force into the association of the base, lid and jacket, as well as from one Outer ring part, which is used to absorb the radial component of the cover force (explosive force) and is designed in multiple layers. In this case, the advantage of the compressive stress on the cover is also combined with the tensile stress in a multi-layered manner Parts, which is advantageous from a safety point of view, as this results in a different material behavior in relation to the Steam generator, which is a thick-walled vessel subject to tensile stress is achieved.

In the following, exemplary embodiments of the invention are described with reference to the drawings and their mode of operation is explained. Show it:

Fig. 1 is a schematic elevation of a steam generator indicated by outlines with a burst protection arrangement according to the Invention and axial tensioning elements as connecting means;

FIG. 2 shows the plan view of the arrangement according to FIG. 1; Fig. 3a the detail χ from Fig. 1 in a modified embodiment with a welded and ribbed Support ring and a sheet metal bandage applied to its outer circumference;

FIG. 3b shows the plan view belonging to the front elevation of FIG. 3a; FIG. 4a likewise shows the detail χ according to FIG. 1 in a further embodiment with shrunk onto the support ring Wrestling;

Fig. 4-b shows the associated plan;

Fig. 5 shows the detail Y from Fig. 1, i.e. the engagement of the Spherical shell halves in the butt joint area, and

, Fig. 6 shows a fourth exemplary embodiment with one of cylinder sections Burst protection jacket welded together in the neckline.

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The one in Pig. The burst protection arrangement shown in FIG. 1 is provided for an essentially cylindrical steam generator 1. This is preferably a steam generator that is located in the primary circuit of a pressurized water nuclear power plant, the rest of which Primary circuit components such as the reactor, main coolant pumps and primary coolant lines are also protected against bursting, thus in the worst possible accident (GAU), the break a main coolant line, the crack cannot expand and thus the flow cross-section is limited and also none Fragments can be shot into the containment. Purely for the steam generator 1, this means that in the event of a (albeit very unlikely) break Fragments that might penetrate the steel shell 1a of the steam generator, not through the burst protection can get through, so that the release of radioactive fission products is avoided. In the present case it is around a steam generator 1, which is indicated schematically at 2 with the Main coolant pump is structurally combined; the pump motor is labeled 3 »the shaft feed-through of the pump is labeled 2a. In addition, an inlet chamber 2.1 for the primary medium, a pump suction chamber 2.2 and a pump pressure chamber are also indicated or an outlet chamber 2.3. The chambers are separated from one another in terms of flow by corresponding partition walls 2.4. Finally, the tube sheet is indicated at 1.1 and the U-tube bundle of the steam generator is indicated at 1.2; the primary coolant supply and outflow lines are not shown, but the live steam line 1.3, which will be discussed later.

The burst protection cover, generally designated BS, consists of the Principle of base B, cover D and jacket M made of tensile and pressure-resistant material, in the example shown made of steel. Floor, Cover and jacket B, D, M are by means of axial tensioning elements distributed over the circumference of jacket M and designed as tensioning cables 5 connected with each other. The tension cables 5 each have a threaded shaft 5.1 at their ends (cf. e.g. Fig. 3a), are screwed onto the clamping nuts 5.2. The burst protection jacket M is made up of individual cylinder sections or rings 4 divided, which, as shown, are axially strung together to form the burst protection jacket M, this together with the Bottom B and the cover D after assembly of the tension cables 5 the outer

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Burst protection shell results. Between the outer skin 1a of the steam generator 1 and the jacket M and the cover D are segments made of Druckfestemi heat-insulating material, in the exemplary embodiment so-called Leca concrete, inserted, which in the event of a burst, the compressive forces exerted on them on the jacket M and the Transfer cover D. The division of the jacket M into sections and the insulating intermediate layer into segments 6 is useful, since this facilitates the assembly and disassembly of the anti-burst cover BS, in such a way that it progresses from bottom to top the individual sections and insulating segments can be stacked on top of one another and also for repeat testing There is access to the steam generator. In order to ensure the free thermal expansion of the steam generator 1, it is useful to not to use the tensioning cables 5 or only slightly pre-tensioned, so that their stress occurs only in the event of a burst.

According to the invention, the cover D now consists of an inwardly curved, divided spherical shell and an undivided support ring 7, the spherical shell 8 being a separate component with its outer edge surface inclined in accordance with its concave curvature 8.1 on a correspondingly inclined inner ring surface 7.1 of the support ring 7 is supported (see. Fig. 3a). The support ring 7 is, as can be seen from Fig. 1, in the association of the tensioning elements 5 included, i.e. it serves as the upper radial insert ball bearing, whereas the bottom B forms the lower radial insert ball bearing. In a preferred version the spherical shell 8 is divided into two parts, so that, as shown in FIG. 2, two identical shell halves 8a, 8b are formed. This is special Advantage for a steam generator in which the main steam pipe 1.3, see FIGS. 1 and 2, is led out centrally from its housing cover surface. Namely, if you lay the butt joints the spherical shell 8 so that its extension intersects the pipe axis 1.3 'and the shell parts 8a, 8b are left Eohrleitung 1.3 with sector-shaped cutouts 8.3 of its inner circumference reach around, an easy assembly and disassembly of the cover D is possible without affecting the centricity of the main steam line 1.3 would have to be waived. The removal of the cover D is done in such a way that after removal the tensioning cable 5 of the support ring 7 raised and as far as possible is shifted sideways. Now one cover half 8a

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or 8b can be removed laterally. Then the S-fcützring 7 is moved to the other side and the second cover half 8b or 8a removed. Finally, the support ring 7 is placed on the jacket M again. This jacket M is also referred to as a splinter protection cylinder, even if its puncture is not exhausted because it has to absorb the radial forces in the event of a (very unlikely) longitudinal or circular crack in the steam generator 1 , whereas the axial stress on the base B and cover D of the tension cables 5 is added. The bottom B and the support ring 7 are therefore to be provided with correspondingly dimensioned load-bearing cross-sections.

Pur the support ring 7 'can be the load-bearing cross-section is advantageous according to! 3a, 3b split, where it is shown that the support ring 7 ¹ of an inner ring and an outer ring part 7.2 part is 7.3. As the schematically indicated force diagram shows, the bearing force P exerted by the spherical shell 8 in the area of its compressive stress on the mating surface 7-1 can be broken down into an axial force component P _Q

xL et

and a radial force component P. The inner ring part 7.2 serves to accommodate this axial or vertical component P and introduces this into the axial clamping elements 5.1. the

radial force component P is from the inner ring part 7.2. on the Outer ring part 7.3 transferred, which the latter is accordingly subjected to train, whereas the stress on the inner ring part 7.2 is a compressive stress. The outer ring part 7.3 is for this purpose advantageously formed by a sheet metal effect that on the outer circumference 7.4 of the inner ring part 7.2 is applied »The application can be done in layers with preheating} es however, the sheet metal winding as a whole can also be completed separately and then, with preheating, on the inner ring part 7.2 be shrunk. As Fig. 3a, 3b further show, the inner ring part 7.2 is designed as a ribbed welded construction. It has an end-face flat ring body 7.5 with bores 10 for anchoring the clamping elements 5, and also a wreath axially-radially extending support ribs 7.6, which are in the circumferential spaces 10 'are arranged between the anchoring points 10 of the axial tensioning elements. Finally, the inner ring part 7.2 Attachment ring parts connected to the ribs 7.6. 7.7

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and 7.8, the contact ring part 7.8 forming a conical surface 7.1 inclined by the angle Φ Ä # 60 ° for the contact with the correspondingly inclined counter surface 8.1 of the spherical shell. Depending on the curvature of the spherical shell 8, the angle of inclination of the contact surfaces 7.1, 8.1 can differ upwards or downwards, in particular it is between 40 and 60 ° for practical designs, the dimensions of the axial and radial force components and thus the dimensioning of the Inner and outer ring part can determine. The abutment ring part 7.8 is welded to the individual ribs 7.6 and, due to its approximately double trapezoidal shape, is able to introduce the force components into the ring of ribs, the TJmfangsflache al, the end face a3 and the inclined surface a2 ensure a good frictional connection. The bearing ring part 7.7 is placed on the outer circumference of the rib ring 7.6 and welded to the latter and, together with the flat ring body 7.5, forms an aligned cylindrical closure for applying the sheet metal winding 9. The fitting ring 4.1 placed on the topmost cylinder section 4 with the interposition of a shim ring 4.2 ensures a flat fitting ring 4.1 and thus support of the spherical shell 8 free of local stress peaks on its conical surface 4.3, which is adapted to the curvature of the latter.

In the embodiment of Fig. 4a, 4b are on the inner ring part 7.2 Shrink rings 11 shrunk on. In the illustrated Case there are four shrink ring layers, which after shrinking on the inner ring part 7.2 immovable in their position by screwing on the end-face flat ring body 7.5 and another lower ring plate 7.8 are set. Axial channels 12 on the outer circumference of the inner ring part 7.2 are used for leading through the tension cables. The channels' 12 are in shown case executed as milled grooves. Otherwise, parts that are functionally identical to FIGS. 3a, 3b are also included are given the same reference numerals.

From Fig. 1 it can be seen that the insulating concrete body 6 not only in the jacket area, but also in the cover area as Serve intermediate layer so that they are here for a uniform introduction of force into the spherical shell 8 and thus into the cover D.

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care for. Pig. 1 in conjunction with Pig. 2 also shows that it may be useful to line the inner circumference of the spherical shell 8 with two half-neck parts 13a, 13b, their parting line are preferably offset by 90 ° with respect to the parting line of the spherical shell 8, so that the Prischdampfleitung 1.3 of forces the spherical shell 8 can be kept free. The two spherical shell halves 8a, 8b grip in the parting joint area according to Pig. 5 with trapezoidal groove 8.5 and peder 8.4 into each other under load of columns s for the thermal expansion, so that they can be clearly fixed to each other. Even if the illustrated division of the spherical shell 8 into two parts is particularly advantageous is, then a division into three or more equally sized sectors would be possible, but it should be noted that a division causes a weakening of the vault in too many sectors, this would therefore have to be dimensioned more heavily.

In the Pig. 6, the axially loadable connecting means are formed by circular weld seams 14, by means of which the cylinder sections 4 of the jacket M ^{are welded to one another and the upper end pipe section 4.0 is welded to the support ring 7 1} "of the cover D. Otherwise, parts corresponding to the previous figures also have the same reference numerals The lower end pipe section 4.4 of the jacket M is also connected to the base B by a weld 15, namely here in cross-section V-shaped circular welds 15a and 15b are provided because of the thickness of the base B, which are layered by powder welding or the like. can be produced so that a metallurgically perfect connection is achieved between the anti-burst jacket M and the anti-burst base B. Only the left half of the axial section is shown in Figure 6, it being understood that the arrangement is essentially mirror-symmetrical. The shell parts 8a, 8b ( the part 8b cannot be seen in Pig. 6) of the cover D are by means of e A shear ring 16 is held supported on the support ring 7 ^{t! t} , the shear ring 16 sitting in an annular groove on the inner circumference of the support ring 7 ⁿⁱ and the shell parts 8a, 8b rest with a planar, axially normal ring zone 18 on the protruding shear ring counter surface 17.1. The burst protection cover B, M, D is again assembled from below, the individual cylinder sections 4 being successively welded to one another

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are inserted by inserting the insulating concrete segments 6. Finally, the support ring 7 '' 'welded on, the shell part of the cover D can be brought into position and in its position be fixed by inserting the shear ring 16. It can be advantageous here if the shear ring is in one of the end winding brackets of turbo-generators known per se as an open, for the purpose of inserting, its diameter can be reduced Ring is designed, this ring springing open by loosening a clamping tool (not shown) and into the annular groove 17 is spreadable.

13 claims
6 figures

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Claims (13)

Claims 1.) Burst protection arrangement for essentially cylindrically shaped Steam generator, preferably from pressurized water nuclear power plants, with a burst protection cover surrounding the steam generator with a base, lid and jacket made of tensile and pressure-resistant Material, in particular steel, with the base, cover and jacket connected to one another by means of axially loadable connecting means are connected and the jacket consists of cylinder sections, characterized in that the cover consists of an inside arched, split spherical shell and an undivided support ring consists in that the spherical shell is a separate component with its outer edge surface is supported on an inner ring surface of the support ring and that the support ring by means of the axially loadable Lanyard is included in the association of bottom, lid and jacket. 2. Arrangement according to claim 1, characterized in that the spherical shell is divided into two shell halves. 3. Arrangement according to claim 1 or 2, for a steam generator, in which the live steam pipeline centrally from its housing cover surface is led out, characterized in that the parting joints of the spherical shell through the pipe axis are placed and the spherical shell parts encompass the pipeline with sector-shaped recesses of its inner circumference. 4. Arrangement according to one of claims 1 to 3, characterized in that that the support ring consists of an inner ring part which is used to accommodate the vertical component of the lid force and to initiate this force in the association of the bottom, cover and jacket is used, as well as from an outer ring part, which for The radial component of the Deekelkraft (explosive force) is used and is multi-layered. 5. Arrangement according to claim 4, characterized in that the outer ring part by one on the outer circumference of the inner ring part applied sheet metal winding is formed " 709813/0219 b - Vr - 6. Arrangement according to claim 4, characterized in that the outer ring part is formed by shrink rings which are applied to the outer circumference of the inner ring part. 7. Arrangement according to one of claims 1 to 6, characterized in that that the axially loadable connecting means in a manner known per se by axial tensioning elements in the form of tie rods or tension cables are formed, which are distributed over the circumference of the jacket and anchored on the cover and on the floor are. 8. Arrangement according to one of claims 1 to 6, characterized in that that the axially loadable connecting means are formed by circular welds, by means of which the cylinder sections of the jacket and the upper end pipe section are welded to the support ring of the cover. 9. Arrangement according to claim 8, characterized in that the shell parts of the lid by means of a shear ring on the support ring are held supported, the shear ring sitting in an annular groove on the inner circumference of the support ring and the shell parts with a flat, axially normal ring zone, rest against the protruding shear ring counter surface. 10. The arrangement according to claim 9, characterized in that the shear ring is designed in a manner known per se in the winding head holder of turbo-generators as an open ring which can be reduced in diameter for the purpose of insertion, the ring springing open by loosening a clamping tool and into the annular groove is spreadable. 11. The arrangement according to claim 8, characterized in that the lower end pipe section of the jacket with the bottom through Weld is connected. 709813/0219 12. Arrangement according to one of claims 4 to 6, characterized in that that the inner ring part is made of a ribbed welded construction and for this purpose an end face Has flat ring body, on which the axial clamping elements are anchored, furthermore a ring extending axially-radially Support ribs in the circumferential spaces between the anchoring points of the axial tensioning elements are arranged, and finally bearing ring parts connected to the ribs, which on its inner circumference for contact with the spherical shell and on its outer circumference for contact with the outer ring part are provided. 13. Arrangement according to one of claims 1 Ms 12, wherein between the outer burst protection cover and the steam generator an intermediate layer enveloping the steam generator in the jacket area made of pressure-resistant, heat-insulating material, preferably in the form of insulating concrete segments is, characterized in that the intermediate layer also covers the Deekerbereieh. 709813/0219